The present invention relates to a device for connecting together the ends of tubes for guiding and protecting a cable, and more particularly an optical fiber cable.
Optical fiber cables are replacing copper conductors more and more for data transmission. Nevertheless, optical fiber cables need to be handled with care because of the fragility of optical fibers, thus making them relatively lengthy and expensive to install, and in theory requiring the integrity of each fiber to be verified after installation.
There exists a pneumatic method that greatly simplifies installing optical fiber cables while limiting any risk of them being damaged. The method consists in causing tubes that are connected to one another to pass along the path that is to be followed by the optical fiber cable. Once the tubes have been installed, one end of the cable fitted with a skirt of section slightly smaller than the through section of the tubes is engaged in one end of the tube assembly and air under pressure is injected behind the skirt to push the skirt along the tubes. The tube then serves to guide the cable and once the cable is in place the tubes are left behind in order to protect it.
Coupling devices are usually used for connecting the tubes together in pairs. Each coupling device must serve to ensure that the tubes are connected together in leak tight manner so that the air injected into the tubes can reach a pressure that is high enough to push the cable ends along the entire length of the tubes. The coupling devices also include respective sealing members for ensuring that the cable is clamped in leak tight manner once it is in place in order to isolate the cable from the outside atmosphere and limit any risk of condensation forming and water accumulating inside the tubes. Nevertheless, the sealing member must not prevent the cable from passing through while it is being put into place. That is why the coupling device is generally made in such a manner that the sealing member is retracted while the cable is being put into place and is then caused to project between the tubes so as to come into contact with the outside of the cable once the cable is in place. In present coupling devices, the sealing member is caused to pass from its retracted state to its projecting state by compressing the sealing member axially. The forces that need to be deployed are large and it turns out that manipulating the coupling device is therefore not very practical.